The president does not have the power to create or rewrite legislation — that is Congress’s job. He is not authorized to dispense with or suspend the law. British kings made this practice familiar to the Framers of the Constitution, who deliberately chose to deny such a power to the president.

Yet while history books are filled with disputes between the president and Congress over the scope of their powers, today we are in an era of unparalleled presidential overreach. President Obama openly flouts his duty to faithfully enforce the law — with the battle cry that “we can’t wait” for Congress to act.

To determine if modern presidents have become too powerful, let’s start by referring to the Constitution. Article II charges the president with the duty to carry out the law — to “take care that the laws be faithfully executed.” Contrary to what some more ambitious presidents would have us believe, this was meant to constrain the executive’s power. It’s a duty that includes complying with statutory mandates, enforcing laws and regulations (including prosecuting lawbreakers) and defending the validity of laws in court.

As a practical matter, presidents enjoy wide discretion around how to execute the law, particularly because courts are often reluctant to say the president has abused this discretion or crossed the line into abdication of a constitutional duty. Some judgment is warranted, given the large body of regulations churned out annually by administrative agencies and the ever-growing federal code the president enforces.

Furthermore, it would be impractical for the executive branch to prosecute every violation of every law or regulation, so administrations must prioritize law enforcement resources and may decide not to enforce a particular law against a particular individual or small category of individuals on a case-by-case basis. For example, the government has only passively enforced the draft, and when a draft-dodging young man challenged his conviction on selective prosecution grounds in the 1985 case Wayte v. United States, the Supreme Court ruled in favor of the government because it “retains ‘broad discretion’ as to whom to prosecute.” But prosecutorial discretion can be stretched too thin, becoming the exception that subsumes the rule.

Although it’s a rare exception, many scholars agree that presidents may refuse to enforce a law if they believe it is unconstitutional, since the Constitution is itself the highest law that must be “faithfully executed.” But when presidents disagree with an otherwise constitutional law for policy reasons, or if they would prefer not to enforce a law for political reasons, they must still carry it out. To allow otherwise would “[clothe] the president with a power to control the legislation of congress, and paralyze the administration of justice,” as the Supreme Court noted in the 1838 case Kendall v. United State ex Rel. Stokes.

There are plenty of examples in which past presidents have flexed their executive power by not fully enforcing certain laws: George W. Bush did not fully enforce certain environmental regulations, Bill Clinton failed to enforce gun-safety laws and Ronald Reagan did not enforce the Sherman Antitrust Act. Richard Nixon also failed in asserting a “power of impoundment” to avoid spending congressionally appropriated funds. And going all the way back to our nation’s early years, Thomas Jefferson declined to enforce the Alien and Sedition Acts of 1798 because he believed them to be unconstitutional.

Yet President Obama has taken this to a new level. He has harmed the separation of powers that the Founders so carefully delineated — by delaying implementation of the Affordable Care Act; refusing to enforce federal drug laws under the guise of prosecutorial discretion; and effectively amending our immigration laws by not only delaying deportations but also granting status and benefits to people who have immigrated to the U.S. illegally. In doing so, he has positioned himself as a super-legislator with the power to override the law.

The next president will have a lot of work to do: rolling back Obama’s overreaching policies, repairing the damage to the separation of powers and the Constitution and, importantly, taking care that only those laws Congress has chosen to pass are faithfully executed. It may be difficult to resist the temptation of copying Obama’s actions. But for the sake of our liberties, the next president must comply with the limits the Constitution places on executive power.